Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: POSTERS Rheology

CPP 7.8: Poster

Monday, February 25, 2008, 16:45–19:00, Poster A

Networks in polypropylene / carbon nanotube composites investigated by simultaneous rheological and electrical measurements — Nikolaos Katsikis¹, •Christian Triebel¹, Joachim Kaschta¹, Helmut Münstedt¹, Andreas Funk², and Walter Kaminsky² — ¹Lehrstuhl für Polymerwerkstoffe, Universität Erlangen-Nürnberg — ²Institut für Technische und Makromolekulare Chemie, Universität Hamburg

Electrical conductivity of polymer composites filled with carbon nano-tubes (CNT) can already be reached for concentrations far below 1 vol.%. To achieve such properties, a good distribution of the CNT is essential. This goal is very difficult to reach for polyolefins as their processing in the diluted state, necessary for a good distribution of nanoparticles, is complicated. Polypropylene/CNT composites were developed at the University of Hamburg by using metallocene catalysts. Materials of that kind were investigated by simultaneous measurements of rheological and electrical properties in order to get information on the formation of CNT - networks. For that purpose, a rheometer was equipped with heatable electrodes and a sensitive current measuring system. It was found that the distinct percolation threshold for the electrical conductivity is not reflected in rheological properties which show a more or less continuous change with the volume concentration. A model for an explanation of these findings is presented and discussed.